Informed by primary interviews and observational research conducted by the authors with women prisoners in Northern Ireland, this article focuses on prison as an institutional manifestation of women’s powerlessness and vulnerability, particularly those enduring mental ill-health. It contextualises their experiences within continua of violence and ‘unsafety’. It also considers official responses to critical inspection reports and those of the Northern Ireland Human Rights Commission based on the authors’ research findings. Finally, the primary research demonstrates that three decades on from publication the first critical analyses of women’s imprisonment, the conditions of gendered marginalisation, medicalisation and punishment remain. This is brought into stark relief in the punitive regimes imposed on those most vulnerable through mental ill-health.